public class MyCircularQueue {
    private int[] elem;

    private int front;
    private int rear;
    public MyCircularQueue(int k) {
        // 置空了一个位置浪费了一个空间，因此rear+1和front相遇就满了，因此开辟空间被浪费一格想要足够长就让k+1
        this.elem = new int[k+1];
    }

    public boolean enQueue(int value) {
        if (isFull()) {
            return false;
        }
        elem[rear] = value;
        rear = (rear + 1) % elem.length;
        return true;
    }

    public boolean deQueue() {
        if (isEmpty()) {
            return false;
        } else {
            front = (front + 1) % elem.length;
            return true;
        }
    }

    public int Front() {
        if (isEmpty()) {
            return -1;
        } else {
            return elem[front];
        }
    }

    public int Rear() {
        if (isEmpty()) {
            return -1;
        }
        int index = (rear == 0)?elem.length-1:rear-1;
        return elem[index];
    }
    public boolean isEmpty() {
        return front == rear;
    }

    public boolean isFull() {
        // 置空了一个位置浪费了一个空间，因此rear+1和front相遇就满了
        if ((rear + 1) % elem.length == front) {
            return true;
        } else {
            return false;
        }
    }
}
